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Investigation of entire cadaveric lumbar spine responses to individual and combined loading modes
ETD Collection for Wayne State University (2006)
  • Aditya N Belwadi, Wayne State University
Abstract

Knee airbags, deployable knee bolsters, and seat mounted anti-submarining airbags have been recently introduced in some vehicles to control the lower torso kinematics and reduce the likelihood of a posterior cruciate ligament (PCL) injury. These devices could induce combined anterior shear with flexion load to the lumbar spine not seen previously. Only limited data have been reported in this loading mode. In a series of four test setups, 155 experiments were carried out using seven cadaveric lumbar spines (T12-Sacrum). In the first two, entire lumbar spines were tested non-destructively in compression and tension at 8 mm/s, anterior shear and posterior shear at 4 mm/s, flexion and extension at 3.5°/s, combined anterior shear with flexion, and combined posterior shear with extension on a custom-made test device. In the third setup, Eleven (11) motion segments (consisting of three vertebrae and two discs) were then dissected from these seven lumbar spines and aforementioned non-destructive tests repeated. Finally, eight motion segments were tested to failure in combined anterior shear with flexion loading. ^ Some specimens failed prematurely before the completion of the entire test matrix. Excluding those results, the stiffness values for single loading mode subjected to non-destructive loads were in the same ranges as those reported in the literature. Under the combined anterior shear with flexion load, the average shear force at failure was 1.9 (± 0.6) kN while the average failure moment was 198 (± 76) N.m. These results suggested that the failure thresholds of lumbar spine motion segments under combined loading of anterior shear with flexion were higher than those reported for single mode loading such as anterior shear and flexion only. Results from this study seemed to suggest that combined anterior shear with flexion loading effectively increases the lumbar spine injury tolerance and are consistent with the low incidence of lumbar spine injuries observed in frontal crashes. ^

Publication Date
January 1, 2006
Citation Information
Aditya N Belwadi. "Investigation of entire cadaveric lumbar spine responses to individual and combined loading modes" ETD Collection for Wayne State University (2006)
Available at: http://works.bepress.com/aditya_belwadi/1/